Fresh 5/5A Whole New Thing 2/5Dance to the Music 4/5Life 3/5Stand! 4/5There's a Riot Goin' On 4/5Small Talk 2/5

Among the treasures on YouTube, there is a clip of Sly and the Family Stone in 1969, long before their leader succumbed to crippling cocaine addiction and became a recluse. They are performing a frenzied medley of their hits on American TV. At its climax, Sly Stone and his sister Rose run from the stage and begin dancing. The predominantly white, middle-aged crowd look baffled. Judging by Stone's delighted expression that seems to be the reaction he was after. He heads back to the stage with the confident strut of a man who knows he's doing something remarkable: heading up the first truly integrated band, melding soul and rock together to staggering and long-lasting effect.

It wouldn't end like that, and it didn't start like that either. The first striking thing about the seven albums reissued here is how nondescript Sly and the Family Stone's beginnings were. The title of their debut, A Whole New Thing, noticeably oversold the music. Two years before that TV appearance, you certainly wouldn't have picked Sly and the Family Stone as harbingers of a psychedelic musical revolution on the basis of its surprisingly straight-laced soul or, indeed, the photo of them on the cover, which features saxophonist Jerry Martini wearing socks and sandals.

But within a year, harbingers of a psychedelic musical revolution is precisely what Sly and the Family Stone had become, as evidenced by the sparkling Dance to the Music. Its highlight is Dance to the Medley, an extended version of the title track that features a thumping Motown backbeat, acid-rock guitar solos, soul revue horns, complex harmony vocals and backwards tapes. As it shifts exultantly into its final section - Hey Music Lover! - it sounds as vibrant, groundbreaking and timeless as anything recorded in 1967.

Its follow-up, Life, was an artistic and commercial disappointment, the sound of a band that can't figure out what to do next. The vibrant single Fun aside, the most notable thing is the unwitting prescience of the title track. "Look at Mr Stewart!" it yells, triumphantly. "He's the only person he has to fear!" Eventually, that rather turned out to be the problem.

But not yet. It's testament to the sheer brilliance of much of the songwriting on 1969's Stand! - I Want to Take You Higher's thrilling psychedelic soul, the breezy, undidactic protest song Everyday People, the taut funk of Sing a Simple Song - that you barely notice its two great flaws. Don't Call Me Nigger, Whitey sounds like a spirited attempt to bore racists to death. The protracted blues jam Sex Machine is one of those things that presumably made perfect sense in the late 1960s, like men in kaftans, screwing for peace and the career of Fanny Cradock. Today it just sounds interminable.

What happened next is enshrined in legend. Stone secluded himself in Bel Air, slowed the bubbling funk of Stand! to an agonised crawl and became the first Woodstock generation artist to openly acknowledge that the hippy dream had soured. Indeed, There's a Riot Goin' On is so legendary that any criticism seems vaguely heretical, but there are moments when it sounds precisely as you might expect from an album made by a disillusioned, drug-addicted multimillionaire rock star going slowly mad in a mansion, surrounded by people so stoned they had no idea whether it was night or day. You could argue that no one in their right minds would produce something as fabulously audacious as Family Affair, an implausibly bleak No 1 single whose instrumentation consists entirely of a drum machine and an electric piano, but equally, no one in their right minds would bother releasing Spaced Cowboy, a formless jam session in which yodelling features heavily.

Though doomed to live in the shadow of its predecessor, 1973's Fresh! may be the superior: the same claustrophobic, abstract, drum-machine-driven sound, less of the socio-political import, more consistent, better tunes. The weird, intrictate funk of opener In Time is fantastic, If You Want Me to Stay a perfect pop song, the cover of Que Sera Sera unbearably poignant. Nobody yodels.

The last of these albums, Small Talk, pointed the way forward. Its cover - Stone guffawing in the company of his baby son and Kathleen Silva, the model he married onstage and divorced four months later - attempted to convince the buyer everything was OK, while the slick but lacklustre contents suggested the exact opposite: once an innovator, Stone was now idly following.

Subsequent albums attempted to pull off the same trick with increasing hopelessness. You can feel the desperation in the titles: Heard Ya Missed Me - Well I'm Back!, Back on the Right Track. A few years later, Sly Stone stopped making records altogether. Fans continue to speculate on whether he ever will again.